Vladimir Markin, the head of the Investigative Committee told Russian news agencies the detainees would instead face charges of hooliganism. It carries a maximum sentence of seven years in jail – significantly less than the 15-year maximum that comes with charges of piracy.

Vladimir Chuprov of Greenpeace Russia said: “The Arctic 30 are no more hooligans than they were pirates. This is still a wildly disproportionate charge that carries up to seven years in jail. It represents nothing less than an assault on the very principle of peaceful protest.

“They should be with their families, not in a prison in Murmansk.”

He added: “We will contest the trumped up charge of hooliganism as strongly as we contested the piracy allegations. They are both fantasy charges that bear no relation to reality.

“The Investigative Committee also say they may charge some activists with use of force against officials, carrying up to 10 years in jail.”